Economical with Energy

How much power does your modern LCD or plasma TV use when it is on? And how much when it is supposed to be 'off'? If you want to be economical with energy at home then you need to know how much power each appliance uses. Handy energy meters are available for this purpose that can just be plugged into a power point and then indicate on a display how much power the appliance uses. How accurate are these meters and what can you actually measure with them? We examined a few of these meters in the Elektor laboratory.